Mix together almond flour, cocoa powder, sugar, baking powder, and salt in your mug.
Stir in egg, vegetable oil, and vanilla extract. Stir well until dry ingredients are very well incorporated—about 20 seconds of stirring is best.
Top with chocolate chips. (No need to stir in.)
Microwave for 60-70 seconds—the cake will rise at the end of the bake time but will fall after heating stops. The top of the mug cake should look very slightly wet when you take it out.
Serve immediately, sprinkled with powdered sugar.
Notes
Top Tips - Use a regular ceramic mug. One with a more narrow opening is better than one with a very wide opening, as a narrow tube helps the cake develop volume. - Don’t fill your mug more than halfway. - Don’t worry if your cake deflates a bit after it comes out of the microwave—this is going to happen with a mug cake recipe. - Check the wattage of your microwave—you may need to adjust your cooking time more or less. This recipe is tested with a 800-watt microwave, and 65 seconds was the sweet spot for me!Now that you’re happy with your cake, let’s move on to the fun part—toppings! Besides powdered sugar, you can top your cake with a drizzle of caramel or chocolate sauce, or with whipped cream or ice cream. A sprinkle of chopped nuts is delicious too.